Glacier helicopter tours in New Zealand: Franz Josef, Fox and Tasman

Franz Josef — Kā Roimata o Hine Hukatere in Māori — is the one directly above the village, and the one every flight starts with. It is not the longest of the three but it is by far the steepest, and that is what makes it worth flying over: the ice falls out of the Southern Alps in a staircase of seracs and crevasses that no walking route crosses.

From the air the sequence reads clearly. Grey moraine and braided riverbed at the bottom, then the terminal face, then two kilometres of chaotic broken ice, then the névé — the clean white snowfield that feeds all of it. Flights land on the névé.

Fox Glacier is twenty-five kilometres south and about two kilometres longer. It has its own village, its own operators and its own flights, and from Franz Josef it is a five-minute hop over the divide.

Fox is a straighter, wider river of ice with a longer valley below it. It photographs differently: where Franz Josef is dramatic and broken, Fox is long and legible, and you can usually see most of its length in one frame. The eighteen and thirty-five minute flights from Franz Josef both reach it.

Tasman Glacier is on the eastern side of the divide, below Aoraki / Mount Cook, and at twenty-three kilometres it is the longest in New Zealand. It is also the flattest of the three, a broad grey-white plain of ice with a terminal lake at the bottom.

Reaching it from Franz Josef means crossing the Alps, which is the real reason to book a thirty or thirty-five minute flight: the crossing itself, with Aoraki off to one side and ice in both directions.